n = int(input())
s = input().strip()

left = 0
right = 0
total_L = 0
total_R = 0
total_d = 0
valid = False

for i in range(n):
    c = s[i]
    if c == '(':
        left += 1
    else:
        right += 1
    d = left - right
    if d >= 0:
        total_L += left
        total_R += right
        total_d += d
        valid = True

if valid:
    min_val = min(total_L, total_R)
    print(2 * min_val)
else:
    print(0)